This invention relates to splat cooled amorphous magnetic materials.
Up to the present, it has already been well known that the splat cooled amorphous materials exhibit a number of unusual relevant properties and thus, considerable efforts are being undertaken to develop their useful applications.
By way of example, recording techniques are recently on the trend toward the high magnetic density recording and, such recording mediums as having high magnetic coercive force have been commercially available. Consequently, the demand is quite keen to obtain materials having high saturated magnetic flux density (Bs) for use as magnetic core materials of recording heads. However, in general, the materials to be used for the magnetic core materials must satisfy other requirements with respect to the material property in addition to the high saturated magnetic flux density (Bs). Namely, the materials described above are further required to show high stability of magnetic characteristics in a wide range of external stress, high corrosion resistance, high wearing resistance, high thermal stability, etc. Furthermore, so far as transformer cores are concerned, in addition to the high saturated magnetic flux density, low core loss as well as high thermal stability of magnetic characteristics are required.
According to prior research works, it has already been found that the splat cooled amorphous materials exhibit high mechanical strength (for example, 900 with respect to Vickers hardness). Thus, one can easily understand that the splat cooled amorphous materials have high wearing resistance. Some reports have already confirmed the high corrosive resistance of the splat cooled amorphous materials. However, large internal stresses are accummulated in the rapidly cooled amorphous magnetic material, and efforts to improve this defect have been executed by the use of heat treatment of the materials. In order to execute an easy heat treatment of the amorphous magnetic materials, the crystallization temperature (Tx) of the amorphous magnetic material must be generally higher than its Curie temperature (Tc). When the heat treatment is performed in the temperature range as defined by the relationship of Tc&lt;T.sub.A &lt;Tx, both of the permeability and the thermal stability are enhanced. The condition of Tx&gt;Tc is thus one of the requirements for improving the magnetic permeability of the amorphous magnetic materials. The splat cooled amorphous magnetic materials proposed up to the present can satisfy one or two requirements with respect to the relevant properties, but there have not yet been proposed such splat cooled amorphous magnetic materials as those which can simultaneously satisfy all the requirements.